1. Technical Field
The disclosure relates to a polishing method for finishing a surface of an optical element such as a lens.
2. Related Art
Generally, in order to finish a surface of an optical element such as a lens, a prism, and a mirror, polishing is performed by sliding a polishing tool and a workpiece against each other. Specifically, a polishing sheet made of polyurethane adheres to such a polishing tool, and abrasive grains for polishing, interposed at an interface between the polishing tool and the workpiece, are used for polishing.
In recent years, there has been a demand for an optical element with high shape accuracy which is free from surface distortion. Accordingly, a polishing device for improving finishing accuracy of a workpiece has been proposed. Specifically, such a polishing device includes means that rotates a polishing tool, means that rotates the workpiece, and swing means that swings a relative positional relation between the polishing tool and the workpiece (for example, refer to Japanese Laid-open Patent Publication No. 09-300191).
In addition, a polishing tool to polish a workpiece has also been proposed, in which a distance from a rotation axis of the polishing tool to an outer peripheral shape of a work surface that polishes the workpiece is not constant in a rotation direction (for example, refer to Japanese Laid-open Patent Publication No. 2006-136959).